WASHINGTON, DC.- With a $45 million federal appropriation to the Smithsonian Institution, the Smithsonian Environmental Research Center in Edgewater, Md., on the Chesapeake Bay, will start building today what is expected to be one of the most energy-efficient laboratories in the country. Sustainable houses and office buildings have seen their popularity surge in recent years. But creating a more sustainable laboratory, especially one with chemistry research, where fume hoods can consume up to three times as much energy as an average home, presents a greater challenge. The expanded and remodeled Mathias Laboratory will reduce its environmental impact on all fronts, from where it gets its power to where it gets its materials. Analysts estimate it will consume at least 37 percent less energy, and emit 37 percent less carbon dioxide, than a similar building that meets baseline LEED certification standards.